“We already follow the rules, but just don’t get the benefit for our New Zealand exporters. Joining up to the GPA will improve all access and reduce costs for exporters,” said Steven Joyce, economic development minister.

Countries that are members of the GPA promise to open public contracts to businesses from other member states. It also sets out rules member countries must adhere to relating to competition and openness.

There are currently 42 member countries, including the US, Japan and the 27 countries of the European Union. “Member countries have agreed to revised coverage that will see this amount increased by US$80 – 100 billion (£51 - £64 billion) - each year. The value will also go up as new countries, including China, come on board,” said trade minister Tim Groser.

To join the New Zealand government must demonstrate that its procurement rules adhere to those stated in the GPA. The accession process is expected to take two years.